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A role for nonphysical barriers to gene flow in the diversification of a highly vagile seabird, the masked booby ( Sula dactylatra )
Author(s) -
STEEVES TAMMY E.,
ANDERSON DAVID J.,
FRIESEN VICKI L.
Publication year - 2005
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2005.02713.x
Subject(s) - biology , biological dispersal , gene flow , phylogeography , evolutionary biology , population , clade , haplotype , seabird , isolation by distance , ecology , zoology , genetic variation , phylogenetics , gene , genetics , demography , sociology , genotype , predation
To test the hypothesis that nonphysical barriers to gene flow play a role in the divergence of low‐latitude seabird populations, we applied phylogeographic methods to mitochondrial control region sequence variation in a global sample of masked boobies ( Sula dactylatra ). In accord with previous studies, we found that Indo‐Pacific and Atlantic haplotypes form two divergent lineages, excluding one haplotype previously attributed to secondary contact between the Indian Ocean and the Caribbean Sea. Within the Indo‐Pacific and the Atlantic, we found a relatively large number of haplotypes, many of which were unique to a single population. Although haplotypes from most populations were found in more than one higher‐level clade, nested clade analysis revealed a significant association between clades and geography for the majority of higher‐level clades, most often interpreted as a consequence of isolation by distance. We found low levels of gene flow within Indo‐Pacific and Atlantic populations, and a significant correlation between gene flow and geographical distance among Indo‐Pacific populations. We estimate that Indo‐Pacific masked boobies experienced rapid population growth ∼180 000 years ago and that the majority of Indo‐Pacific and Atlantic populations diverged within the last ∼115 000 years. These combined data suggest that the predominant pattern between Indo‐Pacific and Atlantic populations is long‐term isolation by physical barriers to gene flow. In contrast, populations within these regions appear to have diverged despite few obvious physical barriers to gene flow, perhaps as a consequence of limited natal dispersal combined with local adaptation and/or genetic drift.